Technical Laboratory Bulletin
Topic: Prothrombin Gene Mutation, G20210A
Test Name
Test Code
Method
Changes
Specimen
Test Schedule
Date: 1/1/05
Prothrombin Gene Mutation (also known as Factor II)
PTDNA
Real-Time PCR
Reduced specimen requirement
0.5 mL of whole blood in an EDTA tube
Tested every Thursday
Change:
Effective January 1, 2005, the volume of whole blood necessary for the performance of Prothrombin Gene
Mutation testing is reduced to a minimum of 0.5 mL of whole blood in an EDTA tube. Volumes less than 0.5
mL may lead to failed isolations due to the dilution of the blood with anticoagulants.
Indications:
 History of recurrent venous thrombosis.
 First venous thrombosis at <50 years of age in the presence of an acquired risk factor.
 First venous thrombosis at any age and no associated acquired risk factor.
 First venous thrombosis at an unusual anatomic site such as cerebral, mesenteric, portal, or hepatic vein.
 First venous thrombosis in a subject with a first-degree family member who has had a venous
thrombosis before age 50.
 First venous thrombosis related to pregnancy, puerperium, oral contraceptive use or hormone
replacement therapy.
 Women with unexplained pregnancy loss during the 2nd or 3rd trimester.
It is strongly recommended to test for the Factor V Leiden mutation concurrently with Prothrombin Gene
mutation testing.
Thrombophilic Status
Normal
Oral contraceptive (OCP) use
Factor V Leiden, heterozygous
Factor V Leiden, heterozygous + OCP
Factor V Leiden, homozygous
Factor V Leiden, homozygous + OCP
Factor V Leiden, heterozygous + Hyperhomocysteinemia
Prothrombin Gene Mutation, heterozygous
Prothrombin Gene Mutation, heterozygous + OCP
Prothrombin Gene Mutation, homozygous
Heterozygous for Factor V Leiden and Prothrombin gene
mutations (Chest 118(5):1405-1411)
Relative Risk of Venous Thrombosis
1
4
5 to 7
30 to 35
80
>100
20
3
16
Unknown
>160
Result Reporting:
Negative, Heterozygous for the G20210A mutation or Homozygous for the G20210A mutation.
References:
College of American Pathologists Consensus Conference XXXVI: Diagnostic Issues in Thrombophilia.
November 9-11, 2001. Atlanta, Georgia. Conference Synopsis.
Additional Information:
Contact Gene R. Putz, Ph.D., Laboratory Director, NorDx, (207) 885-7809 or Email at putzg@mmc.org.